1. Field of the Invention
The present invention relates to a data transfer technology using DMA.
2. Description of the Related Art
One of the requirements in a multimedia terminal such as a gaming device is to read and write image data and/or audio data frequently. In order to reduce a load imposed on a central processing unit (CPU), data transfer between a memory and an external input and output device is often carried out by using Direct Memory Access (DMA). DMA transfer is a method to transfer data at a high speed between a memory and an input and output device without CPU intervention.
In a system in which DMA transfer is implemented using an interrupt, two interrupts to a CPU is usually generated for a single transfer process. That is, an interrupt is generated when there is a request for DMA transfer from an input and output device and when the DMA transfer is completed. When an interrupt to a CPU is generated, the CPU should handle the interrupt. Therefore, the more frequent the interrupts, the heavier the load on the CPU.